Acta Chim. Slov. 2000, 47, 89-98. 89 THE NOVEL ROUTE FOR SYNTHESIS OF TELLURIUM TETRACHLORIDE, AND REDETERMINATION OF ITS STRUCTURE AT LOWER TEMPERATURE BY X-RAY CRYSTALLOGRAPHY. Abdolali Alemi,a Esmaiel Soleimani,*a Zoya A. Starikovab a : Inorganic Synthesis Laboratory, Faculty of Chemistry, Tabriz University, Tabriz, IRAN Phone : 0098 41 355998, Fax : 0098 41 340191, soleimani@ark.tabrizu.ac.ir b : X-ray Structural Center, General and Technical Chemistry Division, Academy of Science of Russia, star@xrpent.ineos.ac.ru Received 1.12.1999 Abstract The reaction of iodine trichloride with tellurium in a sealed evacuated glass ampoule at 250 oC yields yellow-green, moisture sensitive crystals of TeCl4. The crystal structure of TeCl4 has been determined in low temperature at 100 K from three-dimensional X-ray data collection. The compound crystallizes in space group C2/c of monoclinic system with unit cell dimensions a = 16.846(3)A, b = 10.347(2)A, c = 15.051(3) A, b = 116.87(3) o, Z = 8, V = 2340.2(8) A3 , rc = 3.059 g/cm3 , final R indices [ I>2s (I) ] R = 0.0507, wR = 0.1304 , and R indices (all data) R = 0.0564, wR = 0.1341. The structure consists of tetramers, Te4Cl16, which have a cubane-like structure. The Te atoms occupy the half of the corners with Td symmetry. Each Te atom has been attached to three terminal Cl atoms with an average distance of 2.325A. The coordination of the Te atom is completed to a distorted octahedron by three bridging chlorine atoms with much longer Te-Cl bond lengths (average 2.915A). In the polar limiting case the structure may be described, in a rough approximation, as an arrangement of TeCl3+ ions with nearly C3v symmetry and of Cl- ions. The structure data suggest possible concentration of the nonbonding Te electrons toward the center of the cubane skeleton. A. Alemi, E. Soleimani, Z. A. Starikova: The Novel Route for Synthesis of Tellurium Tetrachloride… 90 Acta Chim. Slov. 2000, 47, 89-98. Introduction The compounds R3EX2 ( R = alkyl, aryl, mixed arylalkyl, substituted aryl ; E = P, As, Sb; X = Cl, Br, I ) and R2FX2 ( R = alkyl, aryl, mixed arylalkyl, substituted aryl ; F = S, Se ; X2 = Cl2, Br2, I2, ICl, IBr) are a subject of considerable current interest [1-6] . They were found significant use as reagent in synthetic organic and inorganic chemistry [7-11] . Recently structural study of these compounds were interested some of the chemists [12-16] .The dihalogen adducts of tertiary phoshphines [17,18] , arsines [2] , tertiary phosphine sulfides [15,19] , selenides [13, 20] , organo-selenium compounds [6, 21] and selenoamides [22-24] have all received considerable study from a variety of research groups in the last few years. It is surprising that many of the dihalogen compounds formed lie close the ionic and covalent borderline are influenced not only by aggregation (solid, liquid, gas) or the nature of solvent, but also by effect of organo-substituents , R , the donor atoms, the indentity of the halogen. Thus, for example, dimethylselenide diiodine adopts a three coordinate charge transfer (CT) structure, Me2Se-I-I [6] whereas the corresponding dibromide adopts a disphenoidal structure, Me2SeBr2 [6] . On the other hand, Me2SBr2 is a charge transfer compelex, Me2S-Br-Br [25] , thus illustrating the importance of the donor atom on the nature of the dihalogen adduct produced. Similarly Ph3As-I-I [2] is a charge transfer complex, whereas Ph3AsBr2 [2] is trigonal bipyramidal. Recently, we have prepared adduct Cl2Se-ICl [26] from the reaction of Se and ICl3 in a sealed evacuated ampoule. In an analogous attempt to synthesis adduct Cl2Te-ICl from the reaction of Te and ICl3, we have obtained yellow-green crystals of TeCl4 by chemical vapour transport reaction. Experimental Iodine trichlorid (ICl3) was prepared by interaction finely powdered iodine crystals and potassium chlorate (KClO3) with together addition gradually dropwise concentrated HCl. Then it was recrystallized in absolute ethanol, and dried over CaCl2 in vacuum. Tellurium was used as purchased. A. Alemi, E. Soleimani, Z. A. Starikova: The Novel Route for Synthesis of Tellurium Tetrachloride… Acta Chim. Slov. 2000, 47, 89-98. 91 Preparation of TeCl4 0.2300 g Te and 0.6130 g ICl3 are filled in a glass ampoule of 25 cm length and 1.5 cm inner diameter. The glass ampoule was evacuated and simultaneously heated with burner flame. The ampoule is placed in a horizontal tube furnace in a temperature gradient from 250 oC to 100 oC with the educt mixture at the hot side. Within three days yellow-green crystals of TeCl4 were transported into the colder part of the ampoule. The yield was nearly quantitative. Due to the high sensitivity towards moist air charging and opening of the reaction ampoule and collection of crystals were performed in the glove box filled with argon atmosphere. Crystal Structure Analysis The single crystal of TeCl4 with size 0.1 x 0.1 x 0.2 mm was fixed to glass capillary tube, which was closed by flame for X-ray diffraction study. Intensity data were collected at 100 oK on a Rigaku AFC7R diffractometer. Preliminary precession photographs showed the monoclinic crystal system with the Laue group 2/m and the centered unit cell. The systematic extinction hol only present for l = 2n was confirmed in the diffractometer data set and led to the space groups C2/c or Cc. The centrosymmetry of the structure with the space group C2/c was confirmed through the structure analysis. 13755 reflections collected with 2q range for data collection 4.78 o to 60.16 o.A structure mode was obtained by direct method and refined by full matrix least square on F2 with anisotropic displacement parameters for all atoms. The maximum and minimum peaks on the final difference Fourier map corresponded to 4.262 and -3.507 eA-3 . Crystallographic data and details of structure analysis are given in Table 1. Table 2 contains the atomic coordinates and equivalent isotropic displacement parameters. Bond lengths and angles are given in Table 3. Table 4 contains the anisotropic displacement parameters. Details of the crystal structure determination can be ordered from FACHINFORMATIONSZENTRUM KARLSRUHE, 76344 Eggenstein-Leopoldshafen, under the depository number CSD-411157. A. Alemi, E. Soleimani, Z. A. Starikova: The Novel Route for Synthesis of Tellurium Tetrachloride… 92 Acta Chim. Slov. 2000, 47, 89-98. Table 1. Crystal data and structure refinement for TeCl4 . Identification code Empirical formula Formula weight Temperature Wavelength Crystal system Space group Unit cell dimensions Z Volume Calculated density Absorption coefficient F(000) Crystal size q range for data collection Limiting indices Reflections collected Independent reflections Completeness to data Max. and Min. transmission Refinement method Data /restraints /parameters Goodness-of-fit on F 2 Final R indices [ I>2s (I) ] R indices (all data) Largest diff. peak and hole TeCl4 Cl8Te2 538.80 100(1) oK o 0.7103A Monoclinic C2/c a = 16.846(3) A, b = 10.347(2) A, c = 15.051(3) A, 8 a = 90 o b = 116.87(3) g = 90 o 2340.2(8) A3 3.059 Mgm-3 6.750 mm-1 1920 0.1 x 0.1 x 0.2 mm 2.39 o to 30.08 o -23 L h L 23 , -14 L k L 14 , -21 L l L 21 13755 3395 (Rint = 0.0831) up to q =30.08 o 98.9 % 1.258 and 0.352 Full-matrix least-squares on F 2 3395 / 0 / 91 1.009 R = 0.0507, wR = 0.1304 R = 0.0564, wR = 0.1341 4.262 and -3.507 eA-3 o A. Alemi, E. Soleimani, Z. A. Starikova: The Novel Route for Synthesis of Tellurium Tetrachloride… Acta Chim. Slov. 2000, 47, 89-98. 93 Table 2. Atomic coordinates [ x 104] and equivalent isotropic displacement parameters [A2 x 103] for TeCl4. Ueq is defined as one third of the trace of the orthogonalized Uij tensor. Atom X Y Z eUq Te(l) 3571(1) 5248(1) 1797(1) 14(1) Te(2) 5019(1) 2317(1) 3918(1) 14(1) Cl(l) 5003(1) 5124(1) 3801(1) 18(1) Cl(2) 3647(1) 2443(1) 1821(1) 19(1) Cl(3) 2526(1) 5208(2) 129(1) 23(1) Cl(4) 2547(1) 5117(2) 2434(1) 23(1) Cl(5) 3661(1) 7498(1) 1878(1) 25(1) Cl(6) 6176(1) 2377(1) 5520(1) 21(1) Cl(7) 3901(1) 2401(1) 4414(1) 20(1) Cl(8) 5003(1) 77(1) 3770(1) 21(1) Table 3. Bond lengths [A] and angles [ o ] for TeCl4 . Te(l)-Cl(4) 2.324(2) Te(l)-Cl(3) 2.325(2) Te(l)-Cl(5) 2.333(2) Te(l)-Cl(l) 2.891(2) Te(l)-Cl(2) 2.905(2) Te(l)-Cl(l)#l 2.925(2) Te(2)-Cl(6) 2.317(2) Te(2)-Cl(7) 2.320(2) Te(2)-Cl(8) 2.328(2) Te(2)-Cl(l) 2.910(2) Te(2)-Cl(2)#l 2.928(2) Te(2)-Cl(2) 2.954(2) Cl(l)-Te(l)#l 2.925(2) Cl(2)-Te(2)#l 2.928(2) Cl(4)-Te(l)-Cl(3) 95.95(6) Cl(4)-Te(l)-Cl(5) 94.55(6) Cl(3)-Te(l)-Cl(5) 94.22(6) Cl(4)-Te(l)-Cl(l) 89.55(5) Cl(3)-Te(l)-Cl(l) 173.28(6) Cl(5)-Te(l)-Cl(l) 89.19(5) Cl(4)-Te(l)-Cl(2) 88.46(5) Cl(3)-Te(l)-Cl(2) 90.18(5) Cl(5)-Te(l)-Cl(2) 174.38(5) Cl(l)-Te(l)-Cl(2) 86.08(4) Cl(4)-Te(l)-Cl(l)#l 171.87(5) Cl(3)-Te(l)-Cl(l)#l 89.59(5) Cl(5)-Te(l)-Cl(l)#l 90.96(5) Cl(l)-Te(l)-Cl(l)#l 84.55(5) Cl(2)-Te(l)-Cl(l)#l 85.56(4) Cl(6)-Te(2)-Cl(7) 95.01(6) Cl(6)-Te(2)-Cl(8) 95.39(5) Cl(7)-Te(2)-Cl(8) 95.28(5) Cl(6)-Te(2)-Cl(l) 90.95(5) Cl(7)-Te(2)-Cl(l) 89.75(4) Cl(8)-Te(2)-Cl(l) 171.53(5) Cl(6)-Te(2)-Cl(2)#1 87.99(5) Cl(7)-Te(2)-Cl(2)#1 174.37(5) Cl(8)-Te(2)-Cl(2)#1 89.17(5) Cl(1)-Te(2)-Cl(2)#1 85.43(4) Cl(6)-Te(2)-Cl(2) 174.08(5) Cl(7)-Te(2)-Cl(2) 89.15(5) Cl(8)-Te(2)-Cl(2) 88.40(5) Cl(l)-Te(2)-Cl(2) 84.85(4) Cl(2)#1-Te(2)-Cl(2) 87.52(5) Te(l)-Cl(l)-Te(2) 95.03(4) Te(l)-Cl(l)-Te(l)#l 95.23(5) Te(2)-Cl(l)-Te(l)#l 94.35(4) Te(l)-Cl(l)-Cl(l)#2 131.75(7) Te(2)-Cl(l)-Cl(l)#2 82.71(5) Te(l)#l-Cl(l)-Cl(l)#2 133.02(5) Te(1)-Cl(2)-Te(2)#1 94.39(4) Te(l)-Cl(2)-Te(2) 93.78(4) Te(2)#1-Cl(2)-Te(2) 92.25(5) Symmetry transformations used to generate equivalent atoms: #1 -X +1, Y, -Z +1/2 #2 -X +1, -Y +1, -Z +1 A. Alemi, E. Soleimani, Z. A. Starikova: The Novel Route for Synthesis of Tellurium Tetrachloride… 94 Acta Chim. Slov. 2000, 47, 89-98. Table 4. Anisotropic displacement parameters [A2 x 103] for TeCl4. The anisotropic displacement factor exponent takes the form: -2p2 [(ha* ) 2 U11 + ... + 2hka* b* U12] . _____________________________________________________________________ Atom U11 U U U U U Te(1) 13(1) 6(1) 23(1) 1(1) 6(1) 2(1) Te(2) 13(1) 4(1) 22(1) 1(1) 6(1) 0(1) Cl(1) 18(1) 8(1) 25(1) -2(1) 8(1) 0(1) Cl(2) 17(1) 9(1) 27(1) 0(1) 7(1) -1(1) Cl(3) 18(1) 20(1) 23(1) 3(1) 4(1) 2(1) Cl(4) 19(1) 20(1) 33(1) 3(1) 14(1) 4(1) Cl(5) 30(1) 6(1) 36(1) 2(1) 13(1) 3(1) Cl(6) 17(1) 16(1) 24(1) -1(1) 5(1) 2(1) Cl(7) 17(1) 13(1) 31(1) -3(1) 12(1) -3(1) Cl(8) 27(1) 5(1) 30(1) 0(1) 13(1) 0(1) Results and Discussion Synthesis of TeCl4 In the attempt for preparation adduct Cl 2Te-ICl from the reaction of Te and ICl3, yellow-green crystals of TeCl4 were obtained. The reaction path way can be as following: heat 1) ICl3 ICl + Cl2 > TeCl 4 2) Te + 2 Cl2 It is clear that at 250 oC, first some ICl3 dissociate to chlorine and iodine chlroride. Then tellurium reacts with fresh chlorine and forms yellow-green crystalline compound TeCl4, which are separated from the vapour phase in the cold side of the ampoule. Crystal Structure of TeCl4 The structure consists of isolated tetramers Te4Cl16 which have only Cl .... Cl van der Waals contacts to neighboring Te4Cl16 molecular units. These tetramers have a cubane-like structure with Te and Cl atoms occupying alternatively the corners of Te4Cl4 A. Alemi, E. Soleimani, Z. A. Starikova: The Novel Route for Synthesis of Tellurium Tetrachloride… Acta Chim. Slov. 2000, 47, 89-98. 95 cubane skeleton. Figure 1 shows the unit cell, Figure 2 shows a detailed view of structure and the connection of atoms, and Table 3 shows bond length and bond angles. Figure 1 . Representation of the unit cell of Te4Cl16. A. Alemi, E. Soleimani, Z. A. Starikova: The Novel Route for Synthesis of Tellurium Tetrachloride… 96 Acta Chim. Slov. 2000, 47, 89-98. Figure 2. Perspective view of the structure of Te4Cl16 group. In fact is built of TeCl3+ and of Cl- ions with strong cation-anion interaction o (average 2.90 A ). Every Te atom has three terminal atoms at an average bond distance of o 2.325A . Together with these it forms an equilateral trigonal pyramid with mean bond angles Cl-Te-Cl of 95.06 o. Comparable values are found in TeCl3MoOCl4 [27] (Te-Cl 2.302Ao , Cl-Te-Cl 95.4 o) , (TeCl3)2MoCl6 ( Te-Cl 2.311Ao , Cl-Te-Cl 95.13o ), and (TeCl3)2ReCl6 [28] ( Te-Cl 2.303Ao , Cl-Te-Cl 95.13o ). A. Alemi, E. Soleimani, Z. A. Starikova: The Novel Route for Synthesis of Tellurium Tetrachloride… Acta Chim. Slov. 2000, 47, 89-98. 97 Like in nearly all compounds containing TeX3+ ( X = F, Cl, Br, I ) strong cation-anion interaction were observed in [(TeCl3+) Cl-]. The coordination of Te is completed to a strongly distorted octahedron by three bridging Cl atoms of Te4Cl4 cube with much longer bond distances (average 2.915 Ao ) and mean bond angles (Cl-Te-Cl) of 85.50o. oo o Comparable Te-Cl bond length values are found 2.938 A , 2.929 A and 2.941 A in the TeCl3MoOCl4 [27] , (TeCl3)2MoCl6 ,and (TeCl3)2ReCl6 [28] respectively. This distortion of TeCl6 octahedron active lone pair electron on the tellurium atom sticking out forward the longer distant face of the octahedron. The low-temperature structure of TeCl4 was similar in all essential details with earlier studied [29] at room temperature. However, our low-temperature experiment allowed improving substantially the accuracy of the final geometrical parameters. Since, TeCl4 have a partially ionic character, which enables it to react with strong Lewis acid to form ionic adducts. The role of the halide ion acceptor can be filled not only by halides of main group elements like AlCl3, BiCl3, AsF6 or SbF6, but by metal halides of subgroup element as well, such as TiCl4, NbCl5, FeCl3, UCl5, MoOCl4, ReCl4, or AuCl3, MoOCl3, VOCl3 also proved to be a suitable Lewis acid. So far compounds TeCl3MoOCl4 [27] (TeCl3)2MoCl6 [28], TeCl3MCl6 [30] ( M = Sb, Nb, Ta ) were prepared by acid-base Lewis adducts. References [1] N. Bricklebank , S. M. Godfrey, A. G. Mackie, C. A. McAuliffe, R. G. Pritchard, J. Chem. Soc., Chem. Commun. 1992, 355-356. [2] N. Bricklebank, S. M. Godfrey, H. P. Lane, C. A. McAuliffe, R. G. Pritchard, J. M. Morenao, J. Chem. Soc., Dalton Trans. 1995, 3873-3879. [3] N. Bricklebank, S. M. Godfrey, H. P. Lane, C. A. McAuliffe, R. G. Pritchard, J. Chem. Soc., Dalton Trans. 1994, 1759-1763. [4] G. Allegra, G. E. Wilson, Jr. E. Benedetti, C. Pedone, R. Albert, J. Amer. Chem. Soc. 1970, 92, 4002-4006. [5] F. Cristiani, F. Demartin, F. A. Devillanova, F. Isaia, G. Saba, G. Verani, J. Chem. Soc., Dalton Trans. 1992, 3553-3560. [6] S. M. Godfrey, C. A. McAuliffe, R. G. Pritchard, S. Sarwar, J. Chem. Soc., Dalton Trans. 1997, 1031-1036. [7] J. M. Aizpurua , C. Palsmo, Synthesis, 1982, 684-687. [8] N. Bricklebank, S. M. Godfrey, C. A. McAuliffe, R. G. Pritchard, J. Chem. Soc., Dalton Trans. 1996, 157-160. [9] S. M. Godfrey, C. A. McAuliffe, R. G. Pritchard, J. M. Sheffield, J. Chem. Soc., Dalton Trans. A. Alemi, E. Soleimani, Z. A. Starikova: The Novel Route for Synthesis of Tellurium Tetrachloride… 98 Acta Chim. Slov. 2000, 47, 89-98. 1996, 3309-3311. [10] S. M. Godfrey, Nicholas Ho, C. A. McAuliffe, R. G. Pritchard, Angew. Chem., Int. Ed. Engl. 1996, 35, 2344-2346. [11] S. M. Godfrey, K. J. Kelly, P. Kramkowski, C. A. McAuliffe, R. G. Pritchard, J. Chem. Soc, Chem. Commun. 1997, 1001-1002. [12] F. Ruthe, W. W. du Mont, P. G. Jones, J. Chem. Soc, Chem. Commun. 1997,1947-1948. [13] S. M. Godfrey, S. L. Jackson, C. A. McAuliffe, R. G. Pritchard, J. Chem. Soc, Dalton Trans. 1997, 4499-4502. [14] M. Arca, F. A. Devillanova, A. Garau, F. Isaia, V. Lippolis, G. Verani, Z. Anorg. Allg. Chem. 1998, 624, 745-749. [15] D. C. Apperley, N. Bricklebank, S. L. Burns, D. E. Hibbs, M. B. Hursthouse, K. M. Abdul Malik, J. Chem. Soc, Dalton Trans. 1998, 1289-1292. [16] N. Bricklebank, S. M. Godfrey, H. P. Lane, C. A. McAuliffe, R. G. Pritchard, J. M. Morenao, J. Chem. Soc, Dalton Trans. 1995, 2421-2424. [17] N. Bricklebank, S. M. Godfrey, C. A. McAuliffe, P. Deplano, M. L. Mercuri, J. M. Sheffield, J. Chem. SocDalton Trans. 1998, 2379-2382. [18] S. M. Godfrey, C. A. McAuliffe, I. Mushtaq, R. G. Pritchard, J. M. Sheffield, J. Chem. Soc, Dalton Trans. 1998, 3815-3818. [19] W. I. Cross, S. M. Godfrey, S. L. Jackson, C. A. McAuliffe, R. G. Pritchard, J. Chem. Soc, Dalton Trans. 1999, 2225-2230. [20] S. M. Godfrey, S. L. Jackson, C. A. McAuliffe, R. G. Pritchard, J. Chem. Soc, Dalton Trans. 1998, 4201-4204. [21] S. M. Godfrey, C. A. McAuliffe, R. G. Pritchard, S. Sarwar, J. Chem. Soc, Dalton Trans. 1997, 3501-3504. [22] F. Cristiani, F. Demartin, F. A. Devillanova, F. Isaia, V. Lippolis, G. Verani, Inorg. Chem. 1994, 33, 6315-6324. [23] P. D. Boyle, W. I. Cross, S. M. Godfrey, C. A. McAuliffe, R. G. Pritchard, S. J. Teat, J. Chem. Soc, Dalton Trans. 1999, 2845-2852. [24] P. D. Boyle, W. I. Cross, S. M. Godfrey, C. A. McAuliffe, R. G. Pritchard, S. J. Teat , J. Chem. Soc, Dalton Trans. 1999, 2219-2224. [25] B. Regelmann, K. W. Klinkhammer, A. Schmidt, Z. Anorg. Allg. Chem. 1997, 623, 1633-1638. [26] A. Alemi, J. Beck, E. Soleimani, publication in preparation. [27] J. Beck, Z. Naturforsch. 1991, 46 B, 183-186. [28] J. Beck, P. Biedenkopf, K. Mueller-Buschbaum, Z. Naturforsch.1996, 51 B, 727-732. [29] B. Buss , B. Krebs, Inorg. Chem. 1971, 10, 2795-2800. [30] F. W. Poulsen , R. W. Berg, J. Inorg. Nucl. Chem. 1987, 40, 471-476. Povzetek Navedena je nova metoda sinteze telurjevega tetraklorida iz jodovega triklorida in telurja v evakuirani stekleni ampuli pri 250 °C. Nastanejo za rentgensko strukturno anal izo primerni kristal i. Ponovno je dol ocena struktura pri 100 K. Strukturo sestavljajo tetrameri Te4Cl16, ki imajo kubanu podobno zgradbo. Telurjev atom je obdan s tremi klorovimi atomi s poprečno razdaljo 2.325 Â, oktaedrično koordinacijo pa dopoljnjujejo še trije mostovni klorovi atomi na poprečni razdalji 2.915 Â. A. Alemi, E. Soleimani, Z. A. Starikova: The Novel Route for Synthesis of Tellurium Tetrachloride…